About 80% of all U.S. avocados are descendants of Rudolph Hass's glorious tree.

The dramatic upward-curving roof is one of the most iconic examples of Googie architecture that still stands today.

This former stomping grounds of the most eminent astronomers of the early 20th century.

From the sky, a kaleidoscope of color brightens the grey landscape of the San Francisco Bay.

An expansive book store, art gallery, and curio shop with wares ranging from tarot cards to novelty socks.

World's largest collection devoted to one fruit.

A library and museum dedicated to typography.

A promotional sun clock on the site of San Francisco's great raceway.

A collection of memorabilia from the Beat era in the back of a San Francisco bookstore.

A bigger-than-life pun that has become a beacon of altruism.

This shop and studio is dedicated to the art of the book, from letterpress to bookbinding.

A multimedia experience that chronicles the atrocities of racism.

In this century-old literary safehouse, print is alive and well.

Once thought to be the oldest living tree in the world, Methuselah was germinated before the Egyptian pyramids were built.

A "Titanic" superfan changed his name to Jack and set up this strange shrine to the blockbuster, complete with Korean food and Tarot readings.

The now-abandoned tunnels were built for the transcontinental railroad on the route where the first wagon train entered California.

Historic funicular railway, believed to be the shortest railroad in the world.

Trails through lava-carved tube-caves display sparkling bacteria and a rich history.

San Francisco's newly reopened hands-on science museum.

A walk-in working camera obscura produces 360-degree live images of the San Francisco coast.

A library of rare occult books in Los Angeles.

Olfactory delights in San Francisco's Botanical Gardens.

Carnivorous plants, medieval aphrodisiacs, and the largest original wood structure glass conservatory in the western hemisphere.

World's largest collection of serial killer artwork and other macabre exhibits.